Backend Engineer - Rust at connecthum | Paris

Join us at iliad-free in Paris as a Staff Engineer specializing in Python. You will take on a pivotal role in our ambitious program aimed at modernizing and evolving our backend systems.Your primary responsibility will be to lead the technical direction of our information system backend, which manages all Free subscribers, including subscription processes, subscriber spaces, and additional services such as video streaming and mobile phone sales.In this role, you will develop a deep understanding of complex business processes executed by our system, such as billing for third-party services, subscription management, and fiber optic connections.You will guide the team in defining the architecture of this distributed system while actively contributing to development using Python, ensuring hands-on involvement.Your expertise will drive development practices that prioritize resilience, quality, testability, and speed of delivery. Additionally, you will be instrumental in establishing robust operational methods in a model where development teams manage their solutions in production, with a constant focus on performance and scalability.

Join our dynamic team at Iliad as a Backend Python Developer in Paris! We are looking for passionate and skilled individuals to contribute to our innovative tech projects. You will work closely with cross-functional teams to design and implement robust backend systems, ensuring high performance and responsiveness to requests from the front-end.Key Responsibilities:Develop and maintain server-side applications using Python.Collaborate with front-end developers to integrate user-facing elements.Optimize applications for maximum speed and scalability.Participate in code reviews and contribute to team knowledge sharing.Stay updated with emerging technologies and best practices.

Join our dynamic team at iliad-free as a Staff Engineer specializing in Python development. We are looking for innovative and driven individuals to contribute to our impactful projects in the heart of Paris. This role offers a unique opportunity to work on cutting-edge technologies and collaborate with talented professionals in a vibrant work environment.

At Outsight, we specialize in innovative software solutions that leverage 3D LiDAR data to monitor the movements of people and vehicles.Our advanced Spatial Intelligence data is invaluable for operators of transportation hubs, including airports and railway stations, as well as sports venues, road infrastructure, and industrial sites. This data helps enhance operations while ensuring user safety and satisfaction.Our diverse team of scientists and engineers is dedicated to developing cutting-edge solutions from our offices in Paris, San Francisco, Sophia-Antipolis (Nice), and Hong Kong, with a commercial presence in Spain to support our global outreach.Learn more about us here: Insights about OutsightExplore insightful articles that illustrate our work: How LiDAR helps Airports manage increased traffic and People Monitoring using LiDAR.

Join Octopus Energy, where we challenge the status quo in the energy sector by making it greener, more affordable, and accessible to everyone. Originally launched in the UK, our innovative approach has expanded to France since 2022! We combine cutting-edge technology with a team of dedicated professionals who are passionate about our customers and the transition to renewable energy. In just three years, we have grown to become the fifth-largest energy supplier in France! Our mission? To provide all French citizens with cheaper and greener energy, along with practical solutions to accelerate the ecological transition. Currently, we are developing the next generation of products that empower the shift towards sustainable energy. Whether it's facilitating the transition to solar energy and electric vehicles, launching smart pricing, or scaling renewable energy production, we tackle some of the most complex challenges in the energy field! We do this with speed, creativity, and a singular focus on customer satisfaction. As a member of the Octopus Tech team, you will have genuine autonomy, a diverse range of projects to work on, and the opportunity to create products that make a significant impact on people's lives, helping them reduce their bills, live more sustainably, and enjoy truly engaging experiences. You will collaborate closely with our French teams in marketing, operations, and data, as well as with technical teams from other countries in the group . Above all, you will see the real-world impact of your work on our customers quickly. Within the OE Tech France team, you're not just coding; you're building the technological engine that makes green energy simple and intuitive for everyone in France. You will join a small, agile, and innovative team where seniority and collaboration are paramount:- A strong core: You will work daily with 1 Product Manager, 4 Frontend Developers, and 3 Backend Developers. The Backend team is currently composed mainly of senior profiles, allowing you to thrive in a demanding and stimulating technical environment.- Synergy with Data : You will work closely with data experts to leverage insights that drive our innovations.

About Mistral AIAt Mistral AI, we harness the transformative potential of AI to streamline tasks, enhance creativity, and optimize learning experiences. Our cutting-edge technology seamlessly integrates into everyday workflows.We are committed to democratizing AI through high-performance, open-source solutions and state-of-the-art models. Our comprehensive AI platform is tailored to meet the diverse needs of enterprises, available both on-premises and in the cloud. Notably, our offerings include Le Chat, the AI assistant designed to elevate both personal and professional life.As a dynamic and collaborative team, we are passionate about AI's potential to create a significant societal impact. Our diverse workforce thrives in competitive environments and is dedicated to fostering innovation. With teams spread across France, the USA, the UK, Germany, and Singapore, we embody creativity, humility, and a strong team spirit.Join us in shaping the future of AI and make a meaningful impact. Discover more about our culture at https://mistral.ai/careers.Role OverviewWe are in search of enthusiastic and talented software engineers to join our team. As a Backend Engineer, you will play a crucial role in developing the core systems that power our key products: AI Studio, Le Chat, and Mistral Code. Your contributions will shape the way users and developers interact with our AI platform at scale. You’ll focus on building reliable, high-performance backend systems and APIs that cater to millions of users and developers. Your work will greatly enhance both developer and user experiences, ensuring they are engaging, efficient, and intuitive. We welcome engineers of all levels, from recent graduates to seasoned professionals, who are eager to learn, collaborate, and deliver impactful solutions.Key ResponsibilitiesDepending on your expertise, you will engage with critical components of our technology, which may include:Backend Development- Design, develop, and maintain scalable and robust backend features and APIs using modern frameworks.- Ensure high performance and reliability across our distributed systems.

About the Role airapps is looking for a backend engineer to help build and maintain the systems behind our applications. This position is based in Paris and focuses on developing backend solutions that scale and perform reliably. What You Will Do Design, implement, and maintain backend systems for airapps products Work closely with teammates to solve technical challenges Contribute to a collaborative team environment Who We’re Looking For Experience building backend systems Comfort working with others to solve problems Interest in developing efficient and scalable solutions This is a full-time role in Paris. If building reliable backend infrastructure with a team sounds appealing, airapps would like to connect.

Join us as a pivotal member of the Backend team at amo, where you'll play a critical role in shaping our infrastructure. In the initial months, you will collaborate closely with the team and gradually take charge of key components and features. At this early stage of our journey, we are in search of adaptable engineers who are eager to contribute across multiple facets of our company’s foundation.We appreciate team members who dive deeply into their areas of expertise, fostering a culture of subject matter mastery within our team. This dedication to specialization is a core expectation for every engineer.Our backend team is responsible for both server-side operations and the backbone of the client, as we believe a unified team can more effectively manage topics like networking, data modeling, management, and synchronization.As a Backend Engineer, your daily responsibilities will include:Building the FutureYou will develop robust systems designed to handle significant traffic, vast amounts of data, and an unparalleled rate of scaling. Your toolkit will include cutting-edge technologies, elegantly crafted code, and systems built for seamless horizontal scaling.Ensuring Cross-Platform CohesionBeyond server-side development, you will be involved in the enhancement and maintenance of a Rust component shared between iOS and Android. This component primarily focuses on networking, data synchronization, and data-oriented feature logic, benefiting from a single codebase. You will collaborate with mobile engineers to ensure a consistent experience across platforms and bridge the gap between mobile development and backend architecture for a cohesive user journey.Innovative Feature DevelopmentEngage in brainstorming sessions to design and implement unique features that distinguish us in the marketplace.Commitment to Continuous ImprovementWe value mutual learning and staying updated with industry trends and emerging technologies, encouraging fresh ideas and contributions to our culture of continuous improvement.Ownership of Your DomainYou will monitor analytics and manage system incidents, taking ownership of your responsibilities and proactively addressing issues and bug fixes.

About PreludeAt Prelude, we are pioneering a new standard for user onboarding and authentication in an era where trust, speed, and conversion are paramount.Our innovative solutions streamline user verification, enhancing security and efficiency while transforming authentication into a strategic advantage. Our flagship product boasts the highest price-to-conversion ratio for OTP code delivery, intelligently adapting to utilize the most effective channels in real-time—whether through optimized SMS routing or popular messaging applications like WhatsApp. Additionally, Prelude actively mitigates spam and fraud risks that traditional providers often overlook, thereby safeguarding both profit margins and user experiences.Established in 2022 and supported by prominent venture capital firms, Prelude has rapidly achieved significant market traction and robust financial health, catering to fast-growing companies throughout Europe and making strides into the US market. Authentication is merely the beginning of our journey.With a forward-thinking roadmap and a suite of market-defining products in the pipeline, we are developing a scalable trust platform that empowers businesses to effortlessly onboard users, combat fraud intelligently, and expand confidently across the globe.About Our TeamThe Prelude team consists of former Zenly professionals who have experienced the limitations of current authentication systems firsthand. While developing products that serve millions, we recognized the challenges posed by costly and unreliable SMS authentication, leading to the inception of Prelude.Currently, our team of 40 is based in Paris, dedicated to creating high-performance, secure user onboarding solutions for businesses in Europe and the US. We believe that small, highly skilled teams are more effective than large, fragmented organizations, and we prioritize impact, quality, and agility.We embrace a flat organizational structure that enhances in-person collaboration, facilitating rapid idea exchange, grounded decision-making, and full ownership of our projects.Our core values guide our daily operations:CareWe are deeply invested in our customers, our colleagues, and the quality and reliability of our products.

Overview: We are seeking a talented Product Engineer specializing in Backend Development with Rust to take charge of and enhance the foundational systems that ensure AI safety at a large scale. Your role will involve constructing APIs capable of managing hundreds of millions of requests, implementing real-time policy enforcement, and developing high-throughput data pipelines.About UsWhite Circle is at the forefront of AI Safety, creating the essential safety, reliability, and optimization framework for AI systems. Our platform is built on policies—easily understandable natural-language rules that outline appropriate AI model behavior. We automatically test, enforce, and continuously refine these policies on a massive scale.We have secured $11M in funding from leading investors, founders, and executives from OpenAI, Anthropic, HuggingFace, Mistral, DeepMind, Datadog, Sentry, and others.Our systems process over one hundred million API calls each month.We optimize and train our own LLMs to operate more swiftly and cost-effectively than any publicly available or proprietary models.As a compact and highly focused team, we welcome those eager to tackle challenging problems, deliver their work to production swiftly, and actively shape the future of AI safety.Your Responsibilities:Design and implement backend services in Rust that facilitate real-time policy evaluations at scale, ensuring low latency and high reliability.Take ownership of features from inception to deployment: API design, database schema development, and continuous monitoring and iteration.Engage with different layers of the stack as needed; we prioritize problem-solving over rigid role definitions.Enhance system performance and reliability through connection pooling, caching strategies, query optimization, and observability practices.Collaborate directly with product managers, researchers, and ML teams to convert requirements into effective production systems.Ideal Candidate:You have experience building and deploying backend systems in Rust—beyond mere tutorials, you have real-world production experience.You are well-versed in async Rust (Tokio), web frameworks (Axum, Actix), and database interaction patterns.You possess strong system design fundamentals, capable of assessing trade-offs, failure modes, and scalability.You have hands-on experience with PostgreSQL, adept at crafting efficient queries and designing schemas.

We are seeking a talented and experienced Senior Python Developer to join our dynamic team at iliad-free in Paris. This role offers an exciting opportunity to work on innovative projects and contribute to the development of cutting-edge technology solutions.The ideal candidate will have a strong background in Python programming, experience with web frameworks, and a passion for delivering high-quality software. You will collaborate with cross-functional teams to design, develop, and maintain software applications that meet the needs of our users.

About the Role airapps is looking for a Backend QA Engineer in Paris to help keep our backend systems reliable and high quality. This role works closely with engineers and product managers to improve how we build and test software. What You Will Do Develop and maintain testing frameworks for backend applications Create automated tests to catch issues early and ensure smooth releases Collaborate with team members to refine development and QA processes Help uphold quality standards so our applications meet user needs Location This position is based in Paris.

Note: This position is based in Paris, France. Relocation and visa support are available if necessary.Achieve the Best Work of Your CareerTrade Republic stands as Europe's largest savings platform, actively engaging in 18 countries and serving over 10 million customers who trust us with more than €150 billion in assets. Our ambition goes beyond that.Our mission is to empower individuals to build wealth through easy, safe, and free access to financial systems. Join us to advance your career while collaborating with exceptional talent and cutting-edge technology, creating a positive impact for millions.Your ResponsibilitiesDevelop and test services and products utilizing modern tools from the JVM ecosystem, including Kotlin, Spring, Vert.x, Hibernate, or jOOQ.Design cloud services with a focus on high availability, low latency, and scalability (primarily on AWS).Implement automated software delivery through GitHub Actions, container-based CI/CD pipelines, and Kubernetes orchestration.Ideal Candidate ProfileA minimum of 5 years of experience in software engineering, preferably within the JVM ecosystem. We welcome candidates from mid to staff level, so whether you are looking to take on more ownership or have extensive experience leading complex systems, we encourage you to apply.Proven experience in developing and deploying scalable features within a service-oriented architecture.A strong dedication to delivering reliable and maintainable software through an iterative development approach and continuous delivery.Experience in building platform services that serve as a foundation for product development (prior experience in platform-focused teams is advantageous).Comfortable working in a flexible hybrid environment, with 2-3 days a week in the office.Why You Should Apply NowOur culture celebrates ownership, excellence, and high energy. We prioritize outcomes and accountability as we strive to tackle one of Europe's significant challenges: closing the pension gap and democratizing wealth. If you resonate with this mission, we want to hear from you!

About H:At H, we are at the forefront of advancing superintelligence through agentic AI. Our mission is to automate intricate, multi-step tasks that are traditionally handled by humans, enabling AI agents to unlock the full potential of human capabilities.We are on the lookout for the brightest minds in AI, those who are as committed to building responsibly and safely as they are to pioneering groundbreaking agentic functionalities. We foster a culture of openness, continuous learning, and collaboration, where every team member's contribution is valued.About the Team:The Product Engineering Team plays a critical role in the successful deployment and management of our Agents and Inference platforms, alongside auxiliary services that support our Research department and lay the groundwork for innovative agentic products and services that we offer to the market.Key Responsibilities:Lead the definition of technical architecture, design, and long-term engineering strategy.Design, develop, and maintain complex, high-performance, scalable systems.Mentor and guide engineers across various teams to foster a culture of technical excellence.Perform comprehensive code and design reviews to ensure adherence to quality and security best practices.Collaborate with Research, Engineering, and stakeholders to deliver impactful solutions.Drive enhancements in system reliability, scalability, and observability.Establish and uphold engineering standards, tooling, and processes.Advocate for technical innovation and proactively manage technical debt.

About MorphoMorpho is at the forefront of Decentralized Finance (DeFi), operating a cutting-edge lending protocol that has recently garnered $50 million in funding from renowned investors, including Ribbit Capital, a16z crypto, and Coinbase Ventures. Our vision is to create an open lending network that democratizes access to the best financial terms for all. With over $10 billion in deposits, Morpho is rapidly redefining the standards of DeFi lending. We are expanding our team to solidify our position as a key player in the emerging internet-native financial ecosystem.Our MissionAt Morpho, we believe in empowering human ambition by providing open access to capital. The current financial landscape is fragmented, leaving many opportunities unseen and many individuals overpaying or entirely excluded. We strive to ensure that capital flows efficiently to where it is most needed, enabling anyone, anywhere, to access optimal terms.LocationThis role can be based in Paris or remotely (candidates located between -5 GMT and +2 GMT are encouraged to apply to ensure effective collaboration with our team).Our Work CultureWe thrive in a fast-paced environment where tackling challenging problems is the norm. As we navigate this evolving market, adaptability is crucial. We foster a culture of open communication where questioning decisions is encouraged. Our team maintains high standards while supporting each other to overcome obstacles and share knowledge. To learn more about our values, visit morpho.org/jobs.Role & ResponsibilitiesAs a Backend Engineer, you will be responsible for designing, building, and maintaining high-performance backend services and APIs that are crucial to Morpho’s user-facing features. Depending on your level of experience, you may take ownership of specific backend domains, mentor junior engineers, and contribute to cross-team initiatives.Your Responsibilities Include:Develop, deploy, and maintain backend services using TypeScript/Node and GraphQL, ensuring reliable and low-latency experiences for users.Design and optimize relational data schemas (PostgreSQL) for accuracy, performance, and maintainability.Collaborate with cross-functional teams including frontend, product, protocol, risk, and security to deliver seamless integrations.

Trade Republic Bank is looking for recent graduates to join the Backend Engineering Program in Paris. This team builds and maintains the core systems behind Europe’s leading savings platform, which serves over 10 million customers across 18 countries and manages more than €150 billion in assets. This program offers a hands-on introduction to backend engineering in a high-impact, real-world setting. Graduate engineers work alongside experienced developers who provide mentorship and support as you move from academic knowledge to building production-ready systems. What you will do Contribute to backend services using modern JVM technologies such as Kotlin, Java, and Spring Assist in designing and developing scalable, reliable systems Work with APIs, databases, and service-oriented architectures Learn to write clean, maintainable, and well-tested code Collaborate with Product and Engineering teams to deliver features for users Gain exposure to cloud infrastructure (AWS), containerization, and CI/CD pipelines Help debug, monitor, and improve system performance Gradually take ownership of well-defined technical projects Learning and growth Participants will see how backend systems are built, deployed, and scaled in a live production environment. The program is designed to help you develop practical engineering skills while contributing to projects that matter to millions of users.

Role Overview Accor S.A. is hiring a Senior Java Backend Developer for its Paris office. This position focuses on building and maintaining backend systems that support hospitality services worldwide. What You Will Do Design, implement, and maintain backend solutions using Java. Work closely with team members to deliver systems that improve both internal operations and guest experiences. Contribute technical expertise to projects that drive service quality and efficiency. Impact Your work will shape the reliability and performance of core systems at Accor, directly supporting the way guests experience our services.

Join Our Innovative TeamBecome a pivotal member of the Healthcare Access stream within the Patient Domain at Doctolib. This stream is essential to our product, guiding patients through their entire journey to accessing care, from finding the right practitioner to booking their appointment and beyond.Our teams are addressing some of the most compelling and impactful challenges in digital health: enhancing search and discovery experiences to enable patients to find the right care faster, developing seamless appointment booking processes that function effectively at scale, designing a delightful and dependable patient app experience, and broadening access to healthcare for new users and diverse use cases across Europe.As a Staff Engineer in this stream, your contributions will directly influence the interfaces and systems utilized by millions of patients daily. Here, web performance, frontend architecture, and user experience are not mere engineering considerations; they are integral to how individuals access their health.

About the APM Data Hub Team The APM Data Hub sits at the heart of Datadog's Application Performance Monitoring suite. This team builds and maintains a backend pipeline that processes, transforms, and routes tracing data at scale after ingestion. The pipeline supports not only APM Distributed Tracing but also a growing set of Datadog products that rely on rich trace data. Role Overview: Engineering Manager I – APM Backend Based in Paris, this role leads a distributed team of 6 engineers. The manager sets the technical direction for a platform that is central to Datadog's product ecosystem. Responsibilities include defining the roadmap for tracing data processing, making trace data accessible to internal consumers, and upholding strong engineering standards for a system that must run reliably at scale. What You Will Do Guide and support a diverse engineering team working on backend data pipelines Shape the technical vision and roadmap for trace data processing Ensure the platform meets high reliability and engineering standards Facilitate collaboration with other product teams that depend on trace data Address complex engineering challenges that affect multiple Datadog products Workplace and Culture Datadog values in-person collaboration and creativity. The company supports a hybrid work model, helping employees balance office life and personal needs.